Seventeen Democrat senators and one independent have called to end America’s ban on gay men donating blood.

The 1983 rule is “outdated, medically and scientifically unsound”, they argued in a letter to the Food and Drug Administration (FDA) yesterday.

Senator John Kerry, who is leading the campaign, said in a statement: “Not a single piece of scientific evidence supports the ban. A law that was once considered medically justified is today simply outdated and needs to end, just as last year we ended the travel ban against those with HIV.”

AFP reports that the letter said: “We write today to express our concerns regarding outdated, medically and scientifically unsound deferral criteria for prospective blood donors.

“With hospitals and emergency rooms across the country in constant and urgent need of blood products, we believe certain blood donor deferral policies should be reviewed and appropriately modified and modernised while ensuring the blood supply meets the highest possible standards.”

Mr Kerry’s office said that men who had had gay sex since 1977 were barred from donating blood, yet people who had had heterosexual sex with someone known to carry the HIV virus were only banned from donating blood for one year.

The US ban was put in place at the height of fears about AIDS in the 1980s.

In response, the FDA said: “The agency understands and respects the desire of everyone, including MSM [men who have sex with men] to donate blood and save lives.

“While FDA appreciates concerns about perceived discrimination, our decision to maintain the deferral policy is based on current science and data, and does not give weight to a donor’s sexual orientation.”

Gay men also face a lifetime blood donation ban in the UK. A review of the policy is to conclude this year.